thanks Anne, very interesting additional information - no one can complain we don't construct in-depth informative sites

I did wonder if the prototype might have been metal - perhaps made using a wooden pattern in the sand sort of thing, but unlikely we shall ever know. I buy very few pieces these days, but agree that passing back to the charity shop is a good idea - at least it keeps these things circulating and lets other folk find them. My opinion would not be that it was made dark deliberately to help with appearance, but again you never know.